As the demand for microfabrication of semiconductor devices and MEMS increases, not only a conventional photolithography technology but also a microfabrication technology in which an uncured resin on a substrate is molded by a mold to thereby form a resin pattern on the substrate have been receiving attention. This technology is also referred to as an “imprint technology”, by which a fine structure with dimensions of a few nanometers can be formed on a substrate. One example of imprint technologies includes a photo-curing method. An imprint apparatus employing the photo-curing method first applies an ultraviolet curable resin (imprint resin, photocurable resin) to a shot area (imprint area) on a substrate (wafer). Next, the resin (uncured resin) is molded by a mold. After the ultraviolet curable resin is irradiated with ultraviolet light for curing, the cured resin is released from the mold, whereby a resin pattern is formed on the substrate.
Here, the substrate used in the imprint process may undergo an overall expansion or contraction resulting in a change in the magnification (size) of the pattern in a biaxial direction that is orthogonal to the surface due to a heating process in a film formation step such as sputtering or the like during the series of device manufacturing steps. Therefore, when an imprint apparatus presses the mold and the resin on the substrate, the pattern magnification formed on the substrate must coincide with the magnification of the pattern portion formed in the mold. When this type of magnification correction is performed using a conventional exposure apparatus, the respective shot sizes during exposure processing are changed by changing the demagnification in the projection optical system in response to the magnification of the substrate, and the scanning speed of the substrate stage. However, an imprint apparatus does not include a projection optical system, and the above type of magnification correction cannot be executed since the resin on the substrate and the mold come into direct contact. In this regard, an imprint apparatus adopts a magnification correction mechanism in which an external force is applied from the side of the mold or the mold is heated to thereby produce an expansion and physically deform the mold.
For example, it is assumed that the above imprint apparatus is applied to the manufacturing process for a semiconductor device having a 32 nm halfpitch. According to the International Technology Roadmap for Semiconductors (ITRS), the overlay accuracy is 6.4 nm. Therefore, to comply with this feature, the magnification correction must also be executed at an accuracy of no more than several nm. On the other hand, a mold (pattern portion) used in the imprint device may also produce a distortion for the following reasons. For example, although the pattern surface of the mold may exhibit an upward incline during preparation, the pattern surface may exhibit a downward incline during use (during pressing). Therefore, there is a possibility of a deformation to the pattern portion due to the effect of gravity or the like during use. Furthermore, the pattern portion is generally formed by a drawing apparatus using an electron beam or the like. During formation, there is the possibility of a distortion due to a distortion aberration in the optical system of the drawing apparatus. Furthermore, even if the pattern portion is prepared without an aberration, if an aberration is produced in the pattern that is preformed on the substrate, the overlay accuracy will be affected. In this regard, as an example of a configuration that inhibits distortion (deformation) in this type of mold, Japanese Patent Laid-Open No. 2010-80714 discloses a stamping apparatus that includes a holding unit configured to hold a plurality of peripheral portions of a mold on a mold chuck and a drive mechanism for positional determination of the holding unit in a Z axis direction with reference to the substrate. This stamping apparatus improves the overlay accuracy by correcting so that the shape of the mold coincides with the shape of the substrate.